1. Field of The Invention
The present invention is directed toward a method and apparatus for stimulating and/or monitoring hemodynamic activity, such as blood flow, in a penis for accelerating the delivery of drugs or pharmacological agents to the penis. The present invention comprises the coupling of an ultrasound source to the outer surface of the penis and transmitting ultrasound energy into the penis at a sufficient frequency and intensity to increase hemodynamic activity. The present invention is also directed to a method for accelerating the delivery of pharmacological agents, such as vasodilating agents, to the penis by increasing hemodynamic activity within the penis.
2. Description of the Prior Art
Erectile dysfunctionality may result from neurogenic, vasculogenic, hormonal, and/or psychogenic causes. The term "erectile dysfunctionality", as used herein, refers to the inability or impaired ability of a male patient to experience a penile erection. The urological arts have devised a number of therapies for treating erectile dysfunctionality. These therapies include psychological, pharmacological, and electrical therapies.
A method and device for electrically stimulating a penile erection is disclosed in U.S. Pat. No. 4,585,005 to Lue et al. The method disclosed in Lue includes the implantation of an electrode on the cavernous nerve. The electrodes of Lue are connected to a receiver that is subcutaneously implanted in the patient. The method and device disclosed in Lue requires surgery. Additionally, if the device disclosed in Lue malfunctions, surgery is required to remove it. Surgery is expensive and time consuming. Additionally, many patients may have emotional or psychological aversions to having electrodes implanted in their penis.
An apparatus for electrically stimulating penile tissue to cause a penile erection is disclosed in U.S. Pat. No. 5,571,118 to Boutos. Boutos discloses the use of a ring having a conductive surface that is placed on the penis and/or the scrotum. There is a risk that such a device may short circuit, if used in an electrically conductive environment, such as a hot tub. This is a major drawback of external electrical therapies, as contrasted with external ultrasound therapies. The use of ultrasound transducers on submerged patients has been applied in other nonanalogous arts, such as extracorporeal shock wave lithotripsy.
An apparatus for electrically stimulating a penile erection is disclosed in U.S. Pat. Nos. 4,542,753 and 4,663,102 to Brennan et al. Brennan discloses a body member for insertion into the rectum of a patient. The body member comprises surface mounted electrodes. Brennan teaches insertion of the body member sufficiently deep into the patient for at least one electrode to contact the prostate gland. The device disclosed by Brennan is highly invasive. Patients may experience physical discomfort from the rectal insertion of the device disclosed in Brennan.
Pharmacological therapies for erectile dysfunctionality include the injection of drugs into the penis. Such methods are disclosed in U.S. Pat. No. 5,236,904 to Gerstengerg et al. and U.S. Pat. No. 4,127,118 to Latorre. Many male patients find the thought of jabbing a hypodermic needle into their penis to be discomforting. Penile injections may also result in the buildup of scar tissue, bleeding, and persistent prolonged erection (priapism). The unacceptability of therapies requiring the intracavernosal injection of drugs into the penis is well documented in the urological arts (See U.S. Pat. No. 5,482,039 to Place et al. and U.S. Pat. No. 5,731,339 to Lowrey; and Padma-Nathan, Treatment of Men With Erectile Dysfunction With Transurethral Alprostadil, The New England Journal of Medicine, 336:1-7, Jan. 2, 1997).
Other pharmacological therapies for erectile dysfunctionality include delivering a drug directly into the urethra of a patient. Methods and devices for transurethral delivery of drugs into the penis are disclosed in U.S. Pat. Nos. 5,242,391 and 5,482,039 to Place et al. These transurethral drug delivery methods involve inserting a shaft into the urethra. The insertion of a shaft up the urethra may cause discomfort in many patients or be objectionable for many of the same reasons that penile hypodermic needle injections are objectionable.
Pharmacological agents for the treatment of erectile dysfunctionality, including vasodilators such as phosphodiesterase (PDE) inhibitors, or alpha adrenergic blockers, may also be delivered orally, transmucosally, transdermally, intranasally and/or rectally. Oral medications are available, pursuant to U.S. Food & Drug Administration (FDA) regulations, under the trademarks VIAGRA (a PDE inhibitor) from Pfizer, Inc. of New York, N.Y., and VASOMAX (an alpha adrenergic blocker) from Zonagen, Inc. of The Woodlands, Texas, or its licensees. Such oral medications are described in U.S. Pat. No. 5,731,339 to Lowrey and U.S. Pat. No. 5,565,466 to Gioco, et al.
Orally, transmucosally, transdermally, intranasally, and/or rectally ingested pharmacological agents for the treatment of erectile dysfunctionality must be dissolved into the blood stream and transported through the body to the penis. Methods of transporting such pharmacological agents to a desired site of effect, are disclosed in U.S. Pat. No. 5,565,466 and are incorporated herein, in their entirety. The time required for such pharmacological agents to be dissolved into the blood stream and transported to a site where they will relax the smooth muscle tissue in the corpora cavemosa, resulting in increased penile hemnodynamic activity sufficient to cause an erection (referred to herein as the "circulatory medication response time"), can be as long as one hour (see website of Zonagen, Inc at www.zonagen.com/html/sexdys.htm). This time period can be unsatisfactory to many men and their consorts, who desire spontaneity in their sexual relations.
The present invention provides an ultrasonic therapy for hemodynamic stimulation of the penis that does not require (1) the injection of drugs into the penis, (2) surgical implantation of electrodes into the penis, or (3) the insertion of electrodes into the rectum. The method of the present invention may be used in an electrically conductive medium, such as a pool or hot tub, without the short circuiting risk present in prior art methods of electrotherapy for penile dysfunctionality. The present invention may be used to reduce the circulatory medication response time by accelerating the circulation of blood comprising a vasoactive or vasodilating agent, thereby reducing its transport time.